1. Field of the Invention
The present invention relates to a plasma display panel (referred to hereinafter as a xe2x80x9cPDPxe2x80x9d), a PDP-substrate, and a method of manufacturing the PDP-substrate. More particularly, the invention relates to a technique for reducing the costs of a PDP and a PDP-substrate, and a technique for improving the brightness or the display quality of the PDP.
2. Description of the Background Art
With the recent trend toward higher definition for PDPs, display cells (referred to also simply as xe2x80x9ccellsxe2x80x9d) of the PDPs have become finer. The display cells are also referred to as xe2x80x9cdischarge cellsxe2x80x9d or xe2x80x9clight emitting cells.xe2x80x9d As an electrode-to-electrode spacing, or a region between adjacent cells, becomes smaller because of the finer cells, discharge (erroneous discharge) becomes prone to occur in the region which is not associated with display. One of the methods of preventing such erroneous discharge in surface discharge type PDPs is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-102280 (1997). This discloses the technique of providing a film for suppressing erroneous discharge on a cathode film of a surface discharge type PDP, the film being formed by patterning titanium oxide (TiO2) or aluminum oxide (Al2O3) using an evaporation and lift-off process.
However, the evaporation and lift-off process involves a relatively large number of process steps to increase costs. More specifically, the evaporation and lift-off process comprises a series of process steps: (i) coating of a resist; (ii) pattern exposure of the resist; (iii) development of the resist; (iv) evaporation of TiO2 or the like; and (v) removal of the resist, and accordingly requires manufacturing apparatuses for the respective process steps. This adds to the costs such as an apparatus cost and a maintenance cost of the manufacturing apparatuses, resulting in an increased costs of the PDPs.
A first aspect of the present invention is intended for a method of manufacturing a plasma-display-panel-substrate including a discharge inhibitor disposed on a surface of a substrate having electrodes for inhibiting formation of discharge in a plasma display panel. According to the present invention, the method comprises the steps of: (a) placing a paste for the discharge inhibitor on the surface of the substrate having the electrodes; and (b) firing the paste to form the discharge inhibitor.
According to a second aspect of the present invention, in the method of the first aspect, the paste comprises a discharge inhibiting material having an average particle size of not greater than about 1 xcexcm.
According to a third aspect of the present invention, in the method of the first or second aspect, the step (a) comprises the step of placing the paste by a printing process.
According to a fourth aspect of the present invention, in the method of the first or second aspect, the step (a) comprises the step of placing the paste by a dispenser process.
According to a fifth aspect of the present invention, in the method of the first or second aspect, the step (a) comprises the step of placing the paste by a coater.
According to a sixth aspect of the present invention, the method of the first or second aspect further comprises the step of (c) placing the paste on a predetermined sheet and drying the paste to form a dry film, wherein the step (a) comprises the step of placing the paste in the form of the dry film.
According to a seventh aspect of the present invention, in the method of the first or second aspect, the step (a) comprises the step of patterning the paste by a photolithographic process.
According to an eighth aspect of the present invention, the method of any one of the first to seventh aspects further comprises the step of (d) forming a cathode film on the surface of the substrate having the electrodes, wherein the step (d) is performed as a final step.
According to a ninth aspect of the present invention, a plasma-display-panel-substrate comprises: a substrate having electrodes; and a discharge inhibitor disposed on a surface of the substrate having the electrodes for inhibiting formation of discharge in a plasma display panel, wherein the plasma-display-panel-substrate is manufactured by a manufacturing method comprising the steps of: (a) placing a paste for the discharge inhibitor on the surface of the substrate having the electrodes; and (b) firing the paste to form the discharge inhibitor.
According to a tenth aspect of the present invention, in the plasma-display-panel-substrate of the ninth aspect, the discharge inhibitor is disposed in a lattice pattern on the surface of the substrate having the electrodes.
According to an eleventh aspect of the present invention, in the plasma-display-panel-substrate of the ninth aspect, the discharge inhibitor is black, white or transparent.
According to a twelfth aspect of the present invention, in the plasma-display-panel-substrate of any one of the ninth to eleventh aspects, the plasma display panel comprises a plurality of display cells, and the discharge inhibitor is disposed in an area corresponding to a space defined between adjacent ones of the display cells.
According to a thirteenth aspect of the present invention, a plasma display panel comprises: a first substrate; and a second substrate disposed in face-to-face relationship with the first substrate, wherein the second substrate comprises: a substrate having electrodes; and a discharge inhibitor disposed on a surface of the substrate having the electrodes for inhibiting formation of discharge in the plasma display panel, and wherein the second substrate is manufactured by a manufacturing method comprising the steps of: (a) placing a paste for the discharge inhibitor on the surface of the substrate having the electrodes; and (b) firing the paste to form the discharge inhibitor.
According to a fourteenth aspect of the present invention, a plasma display panel comprises: a first substrate having a barrier rib; and a second substrate disposed in face-to-face abutting engagement with the barrier rib, wherein part of a surface of the second substrate which is to be in abutting engagement with the barrier rib is in an unsintered state.
In the method according to the first aspect of the present invention, the discharge inhibitor is formed using the paste. The paste may be placed by using, for example, a printing process, a dispenser process or a coater. Alternatively, the paste may be placed after it is dried to form a dry film. The use of the paste increases the flexibility of the method of forming the discharge inhibitor.
Additionally, placing the paste by the above-mentioned processes reduces costs such as an apparatus cost and a maintenance cost of manufacturing apparatuses, as compared with an evaporation and lift-off process. Moreover, patterning the discharge inhibitor by using, for example, a pattern printing process or a dispenser process reduces the number of process steps, as compared with the evaporation and lift-off process. Consequently, the method of the first aspect of the present invention can manufacture the plasma-display-panel-substrate (PDP-substrate) and, therefore, the PDP at low costs.
The method according to the second aspect of the present invention can form the thin-film discharge inhibitor by a process using the paste. Then, such a thin-film discharge inhibitor can ensure isolation between cells. Further, the use of the discharge inhibiting material smaller in particle size makes the discharge inhibitor more transparent, thereby to provide higher light output efficiency.
The method according to the third aspect of the present invention can reduce the time required to form the discharge inhibitor, as compared with the evaporation and lift-off process, to manufacture the PDP-substrate and, therefore, the PDP at lower costs than can the evaporation and lift-off process.
The method according to the fourth aspect of the present invention can directly draw the discharge inhibitor without using a photolithographic process by using, for example, a nozzle which conforms to the pattern width of the discharge inhibitor. Further, the dispenser process is very high in efficiency of utilization of the paste. Therefore, the method according to the fourth aspect can manufacture the PDP-substrate and, therefore, the PDP at lower costs than can the evaporation and lift-off process.
The method according to the fifth aspect of the present invention can place the paste with a more uniform thickness (with variations in film thickness suppressed) than can the printing process even if a printing surface has a large area. Furthermore, although the printing process is disadvantageous in that mesh marks of a screen are left as surface irregularities, the coater can avoid such irregularities.
The method according to the sixth aspect of the present invention can reduce the time required to form the discharge inhibitor, as compared with not only the evaporation and lift-off process but also the printing process and the like. Therefore, the method according to the sixth aspect of the present invention can manufacture the PDP-substrate and, therefore, the PDP at lower costs than can the evaporation and lift-off process and the like.
According to the seventh aspect of the present invention, patterning in the photolithographic process is better in rectilinear property of pattern edges and in position accuracy with respect to electrodes than the pattern printing process, and therefore is more advantageous in process margin.
According to the eighth aspect of the present invention, the cathode film is formed in the final step of the method of manufacturing the PDP-substrate. In other words, this method does not perform the step of forming other components (e.g. the discharge inhibitor) after the cathode film is formed. This prevents the deterioration of film quality of the cathode film. Therefore, the method according to the eighth aspect of the present invention can manufacture the PDP-substrate which can achieve a PDP of high display quality having the good-quality cathode film.
The ninth aspect of the present invention produces the effects of any one of the above-mentioned first to eighth aspects to provide an inexpensive PDP-substrate and, therefore, an inexpensive PDP.
According to the tenth aspect of the present invention, since the PDP-substrate comprises the discharge inhibitor in the lattice pattern, the discharge inhibitor may be disposed between adjacent display cells in the PDP and abut against a barrier rib. The abutment allows the discharge inhibitor to close a clearance between the barrier rib and the PDP-substrate. This prevents leakage of discharge through the clearance, to ensure isolation between adjacent cells, thereby improving image quality. Such an effect is also produced if the discharge inhibitor is thick.
According to the eleventh aspect of the present invention, coloring the discharge inhibitor black provides the PDP-substrate which can improve PDP contrast.
Alternatively, the discharge inhibitor, if colored white, can reflect light generated in the display cells of the PDP. The reflected light may be repeatedly reflected within the cells and finally led out of the PDP. This improves the brightness of the PDP, that is, provides the PDP-substrate which achieves the high-brightness PDP.
Further, the discharge inhibitor, if made transparent, can lead the light generated in the display cells out of the PDP therethrough. This provides the PDP-substrate which achieves the high-brightness PDP.
According to the twelfth aspect of the present invention, the discharge inhibitor can suppress discharge (erroneous discharge) between adjacent display cells. This provides the PDP having high display quality.
The thirteenth aspect of the present invention produces the effects of any one of the above-mentioned ninth to twelfth aspects to provide an inexpensive PDP having excellent display quality (image quality) and the like.
The fourteenth aspect of the present invention can prevent damages to the barrier rib to suppress the occurrence of pixel defects in the PDP.
It is therefore a primary object of the present invention to provide a method of manufacturing a PDP-substrate which can achieve cost reduction of the PDP-substrate and a PDP.
It is another object of the present invention to provide a PDP-substrate capable of improving the brightness or display quality of a PDP, and to provide a high-brightness, high-display-quality PDP using such a PDP-substrate.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.